The nature of consciousness has intrigued philosophers and scientists for thousands of years. But can modern neuroscience ever hope to crack this mysterious phenomenon? At the World Science Festival, an annual celebration and exploration of science held here in New York, a panel of experts debated what scientists can and can’t learn about the mind by studying the brain.

Philosophy of the mind

Plenty of great minds have pondered the meaning of consciousness over the ages, said philosopher Colin McGinn of the University of Miami. The 17th-century French mathematician and philosopher René Descartes famously introduced the notion of mind-body dualism, which holds that the world of the body is fundamentally separate from the world of the mind, or soul, although the two may interact.

In the 19th century, the English biologist Thomas Huxley helped develop the theory of epiphenomenalism, the idea that physical events in the brain give rise to mental phenomena. On the panel, McGinn also talked about panpsychism, the view that the universe is made of minds. [Watch a replay of the program here]

McGinn himself believes that no matter how much scientists study the brain, the mind is fundamentally incapable of comprehending itself. “We’re rather like Neanderthals trying to understand astronomy or Shakespeare,” McGinn said. Human brains suffer from a “cognitive gap” in understanding their own consciousness, he said.

Panelist Christof Koch, a neuroscientist and chief scientific officer at the Allen Institute for Brain Science in Seattle, took issue with McGinn’s view. “I think it’s a defeatist argument,” Koch said. His rebuttal was as colorful as his outfit — a flamboyant Hawaiian shirt and orange pants. “Historically, philosophers have a disastrous record of explaining things,” Koch said. Philosophers are very good at asking questions, he said, but not so good at finding satisfactory answers.

Searching for answers

Koch and the other members of the panel turn to scientific experiments to find answers. For example, the so-called mirror test, developed by psychologist Gordon Gallup in 1970, is a test of self-awareness in babies and animals.

A colored dot is placed on the face of a baby or an animal subject positioned in front of a mirror. If the subject recognizes that the dot in the mirror is the same as the one on its own body, it is said to be self-aware. Babies show self-awareness after about 8 months of age. Animals such as chimpanzees, dolphins and even octopi show it, too.

Koch’s own work focuses on how the activity of the brain’s neurons gives rise to conscious experience. In one well-known experiment, Koch and colleagues discovered that individual neurons can encode abstract concepts, such as a family member or celebrity.

They even found so-called Jennifer Aniston neurons that were active only when a person saw an image of the actress. The conscious experience is of course much more complex than the activity of single neurons, but scientists can learn a lot from the ways in which these brain cells behave and are connected, Koch explained.

Panelist Nicholas Schiff, a neurologist at Weill Cornell Medical College in New York, talked about his work with people recovering from a coma, at the border between consciousness and unconsciousness. “Consciousness is a very graded phenomena,” Schiff said. When a person wakes up, for example, he or she is not fully conscious, but gains awareness gradually.

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